Computer systems typically include one or more different types of resources to store data. Examples of data storage resources include hard drives, optical disks, non-volatile memory chips, volatile memory chips, etc.
In certain instances, access to data in a storage resource in a computer system requires that the corresponding storage resource be powered. For example, in order to write data to or read data from a non-volatile memory chip, the non-volatile memory chip must be powered.
It is known that computer systems and corresponding data storage resources are susceptible to power outages. For example, a primary power source used to power a respective computer may fail at any time. Attempts to access a non-volatile memory chip during a power failure condition may result in corruption of stored data. Computer systems typically include volatile memory resources such as cache or Dynamic RAM (Random Access Memory) to store often-accessed data. In certain instances, the computer system also includes non-volatile memory to store important data that is to be retained even during shut down of the computer system. If data in the volatile memory device is not stored to a non-volatile memory device prior to shut down of the computer system, the data will be lost.
To avoid corruption or loss of data as a result of a power failure, computer systems typically include a bank of capacitors to store holdup energy. When a power failure condition is detected, a power supply in the computer system reverts to using the holdup energy stored in the bank of capacitors (instead of using main power because it is no longer available) to continue to power the computer system during the power failure so that any final writes of data to the non-volatile memory can occur.
Certain conventional power supply systems implement a test to determine a health of a respective bank of capacitors used to store the holdup energy prior to the occurrence of a power failure. For example, one type of conventional power supply system performs a respective energy storage test by electrically coupling an output of the bank of capacitors to a known load for a short duration of time. The monitor circuit monitors a rate at which energy stored in the bank of capacitors is discharged through the known load. Based on the monitoring and the rate at which the output voltage of the capacitors decays over time, the conventional power supply system estimates how much energy is stored in the capacitors.